linux网络协议栈初始化Series---(3)

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Linux Version：2.6.33

提示：本文是介绍linux 网络协议栈初始化！

 

core_initcall级别的初始化方法还有sock_init即

socket的初始化程序。

代码如下

static int __init sock_init(void)
{
    /* Initialize sock SLAB cache. */
    sk_init();
    /* Initialize skbuff SLAB cache */
    skb_init();
    /* Initialize the protocols module. */
    init_inodecache();
    register_filesystem(&sock_fs_type);
    sock_mnt = kern_mount(&sock_fs_type);
    /* The real protocol initialization is performed in later initcalls. */
#ifdef CONFIG_NETFILTER
    netfilter_init();
#endif
    return 0;
}

 

 

sk_init()是根据物理内存大小，设置soket buffer的大小

 

void __init sk_init(void)
{
    if (totalram_pages <= 4096) {
        sysctl_wmem_max = 32767;
        sysctl_rmem_max = 32767;
        sysctl_wmem_default = 32767;
        sysctl_rmem_default = 32767;
    } else if (totalram_pages >= 131072) {
        sysctl_wmem_max = 131071;
        sysctl_rmem_max = 131071;
    }
}

 

skb_init()设置packet buffer 的slab 分配方法。

void __init skb_init(void)
{
    skbuff_head_cache = kmem_cache_create("skbuff_head_cache",
                          sizeof(struct sk_buff),
                          0,
                          SLAB_HWCACHE_ALIGN|SLAB_PANIC,
                          NULL);
    skbuff_fclone_cache = kmem_cache_create("skbuff_fclone_cache",
                        (2*sizeof(struct sk_buff)) +
                        sizeof(atomic_t),
                        0,
                        SLAB_HWCACHE_ALIGN|SLAB_PANIC,
                        NULL);
}